Effective organization of producers is one of the most important factors to increase agricultural production, to obtain quality products and to raise the living standards of farmers. In this research it was studied to determine the factors affecting membership of the Breeders Association, which was one of the most important components of the producer organization, by using structural equation modelling (SEM). The scope of the work was constituted of 3 Breeders Association members organized in the Sivas province of Turkey. A survey was conducted with 369 breeders to collect primary data.The questionnaires were formed of 5 likert type questions for testing SEM. Due to the nature of the SEM, it was based on the theory. First, a theoretical model was created. Factors affecting membership in the model were Economic, Professional, Union activities, Democracy and Organization Awareness and Social and Environmental factors. There were a total of29 variablesunder 5 factors. Confirmatory factor analyses (CFA) was performed for each factor separately. Then first level CFA and path analysis were conducted.The model was not initially confirmed by the data. Therefore, a new model was obtained by modifying the first one.Modifications were made after each analysis conducted. The confirmed model consisted of 16 variables. It was found that all of the identified factors were in the same direction and strong relationship with each other. It was determined that the ways drawn from union activity and social and environmental factors to membership were statistically significant and had a direct impact on membership.It is the first study using SEM on producer organization.It could be used by adapting in different geographical regions and cultures.